Fading

Fading is a process in which Elders die when a Shadowrealm that has been bound to a being's life-force (such as Hekate and her Shadowrealm) is destroyed. They cannot be restored to life, though they can be contacted using Necromancy for a short time after their death.

Contrary to popular belief, Hekate was not killed this way; she was crushed under by the shards Yggdrasil after it was shattered after being stabbed by Excalibur (Yggrasil also stretched across multiple Shadowrealms; the tree may have been bound to her power but it was not the source of it).